1. Field of the Invention
The present invention relates to devices for applying surgical fasteners, and more particularly to a locking mechanism for preventing premature or repeated firing of the surgical fastening apparatus.
2. Background of the Prior Art
Surgical fastening devices for simultaneously applying an array of surgical staples or other types of fasteners are known in the art. Such devices are used for suturing body tissue such as, for example, intestinal and gastric walls with spaced parallel rows of longitudinally aligned stapes. These surgical stapling devices reduce the time of wound closure in a surgical procedure.
Typically, these devices include a fastener cartridge disposed on one side of the tissue to be fastened, and an anvil assembly parallel to the fastener holder on the other side of the tissue to be fastened. The fastener cartridge is moved linearly towards the anvil assembly so that the tissue is clamped between them. The fasteners are driven from the fastener cartridge so that the ends of the fasteners pass through the tissue and are form finished as they make contact with the anvil assembly, thereby producing an array of finished fasteners in the tissue. Optionally, the fastening apparatus may include a knife mechanism for creating an incision between rows of fasteners. The fasteners can be made of metal, non-absorbable polymers, or bioabsorbable polymers such as polyglycolide, polylactide, and copolymers thereof. In addition, the anvil surface may support a plurality of retainers for cooperatively engaging the fasteners after the fasteners pass through the tissue.
In common use are devices in which the fastener cartridge comprises a disposable cartridge removably mounted on a cartridge jaw for supporting and actuating the cartridge. The cartridge is disposable after a single use, i.e. after the fasteners are fired. The fastener device is reusable after reloading with a fresh cartridge, and is generally reusable in a subsequent surgical procedure after cleaning, sterilizing, and reloading. Also known in the art are disposable surgical fastener devices, in which the entire apparatus is disposed of after a single use. Examples of such surgical fastening devices may be found in, among others, Green (U.S. Pat. No. 4,354,628), Green (U.S. Pat. No. 4,665,916), and Green (U.S. Pat. No. 4,568,009).
In the use of surgical fastener devices the possibility arises that the fastener device may be actuated when the cartridge is empty of staples or fasteners. This can occur when the apparatus has been fired once, but the cartridge has not been reloaded or discarded, and may also occur if the apparatus is inadvertently reloaded with a spent cartridge. Under such circumstances the fastening device will fail to suture the body tissue, which can cause harm to the patient due to the surgeon's loss of valuable time. The risk of harm is greatly increased if the apparatus contains a knife mechanism, since it will create an unsealed incision.
To eliminate these dangers to the patient it would be beneficial to provide a device which alerts the surgeon that a new cartridge is required. It would further be beneficial if such a device provides a locking mechanism to actually prevent the surgeon from trying to fire a cartridge that has already been fired and prevent approximation of the jaws should a spent cartridge be loaded into the cartridge jaw. This would save valuable time and reduce the risks to the patient.
Applications Ser. No. 07/936,884 filed Aug. 27, 1992 which is a continuation of Ser. No. 07/622,856 fled Dec. 6, 1990, now abandoned, and Ser. No. 07/928,700 filed Aug. 11, 1992, which is a continuation of Ser. No. 07/704,050 filed May 22, 1991, now abandoned, which is a continuation-in-part of Ser. No. 07/622,856 filed Dec. 6, 1990, now abandoned, disclose a mechanism for applying a plurality of surgical fasteners to body tissue. The devices further provide a locking mechanism for preventing the reapproximation of the jaw members and thus re-firing of the apparatus after a cartridge is spent (i.e. the fasteners have been fired) and the cartridge jaw is withdrawn from the anvil jaw. The locking mechanism disclosed therein is constructed as part of the cartridge, and moreover, the locking mechanism is at least partially located inside of the cartridge.
While this development represented an advance in the surgical fastener art, it is further desirable to provide a locking device that is part of the jaw mechanism of a surgical fastening device in contrast to part of a cartridge that will prevent the re-approximation of a spent cartridge. A locking device that is part of a frame or jaw mechanism relieves a fastener cartridge from cumbersome locking mechanisms, and further, since the locking mechanism will not be disposed of with the cartridge when the cartridge is spent, there is a corresponding reduction in cost in assembly and manufacture.